Filter with high dust capacity

ABSTRACT

A panel filter is provided. The panel filter can have extended life or higher dust holding capacity by one or more of the following provisions of (a) placing the dimpled pattern (compressed region) on the downstream side and outlet face of the media, (b) using the dimpled media in combination with adhesive spacers and embossments, (c) selection of a media that is depth loading rather than surface loading, (d) operating the pleater/embossing assembly in a manner so as to maintain integrity of the dimples and/or other features as described herein.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims the benefit of U.S. Provisional PatentApplication No. 62/047,334, filed Sep. 8, 2014, the entire teachings anddisclosure of which are incorporated herein by reference thereto.

FIELD OF THE INVENTION

This invention generally relates to air filters, and more particularlyrelates to panel air filters that are used, for example, in Heating,Ventilation and Air Conditioning (HVAC) systems, air intakes for gasturbines, or industrial process applications for filtering air.

BACKGROUND OF THE INVENTION

Paneled air filters are commonly used for filtering air in forced airsystems such as Heating, Ventilation and Air Conditioning systems,commonly known as HVAC, as well as air intakes for gas turbines, orindustrial process applications for filtering air. Panel air filtersgenerally comprise a rectangular filter media pack supported by asupport structure in a rectangular configuration such as beingsurrounded and supported by a die cut paper board panel frame or bystrips, bands, scrims, screens or the like, and/or by plastic headerframes.

One common type of filter media used in panel filters is pleated filtermedia that includes a plurality of peaks and valleys. Various prior artimplementations are known to support pleated filter media so that thepanel filters may withstand air pressure during operation. Such priorart includes U.S. Pat. No. 6,709,480 to Sundet et al.; U.S. Pat. No.5,782,944 to Justice; and U.S. Patent Publication Number 2007/0294988,and US 2014/0165839 to Crabtree, both assigned to the present assignee,the entire disclosures of all of which are hereby incorporated byreference thereto.

Generally, in panel filter implementations, there are competinginterests involved. On the one hand, a panel filter must providesufficient dust holding capacity without plugging prematurely to provideadequate filter life span. Additionally, the filter has to provide asuitable particle capture efficiency by removing sufficiently smallparticles such as dust and allergens from the air that are known to beentrained in such forced air ventilation systems.

In some applications, a Minimum Efficiency Reporting Value (MERV) valueof at least 13 or greater is desired.

In other applications such as pre-filters with downstream finishingfilters, a lower MERV value is acceptable such as 8, as in the case ofpre-filters for air intakes for gas turbines. The present applicationhas applicability to these applications too.

For both highly efficient filters and less efficient filters, having ahigh dust load capacity is desirable.

In such applications, on the other hand, it is desirable not to restrictthe flow of air and thereby provide for an open filter structure thatallows for easy air flow through the pleated panel filter. The primaryreason is that plugging is determined by the pressure drop that isexperienced across the filter. Additionally, restricting airflow makesit harder for an HVAC system to deliver hot, cold and/or ventilated airresulting in energy loss. One test for determining the service life of afilter is evaluating dust holding capacity of the filter when the finalresistance or pressure drop across the filter reaches 1.5 inch (3.8 cm)in water gauge pressure at a face velocity of 492 feet (150 meter) perminute, which is a standard ASHRAE 52.2-2012 test. Thus, while arestrictive media is desired so as to enable adequate particle captureefficiency, a more open media is desired for air flow characteristicsand to prevent premature clogging.

As a result, prior art panel filters have often been a compromisebetween these two competing interests.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed toward several different aspects andfeatures that may be used together or independently as outline below.

According to one aspect, a filter media element, comprises a filtermedia sheet having an inlet face and an outlet face, the filter mediasheet being pleated to include a plurality of pleat tips including afirst set of pleat tips along an upstream extent and a second set ofpleat tips along a downstream extent with pleat flanks extending betweenthe first set of pleat tips and the second set of pleat tips. The filtermedia element also comprises a plurality of adhesive elements extendingbetween adjacent members of the pleat flanks and attaching adjacentmembers of the pleat flanks to separate and space the pleat tips in aspaced relation. Further, different filtration regions including acompressed filtration region and a remainder filtration region formedinto the filter media sheet providing the filter media with differentfiltering properties in the different filtration regions.

According to a feature, the compressed filtration region may coverbetween 5 and 50% of the filter media sheet, with the remainderfiltration region comprising the remainder and, wherein the compressedfiltration region defines a compressed thickness, and the remainderfiltration region comprises a regular thickness, the compressedthickness being between 20 and 70% thinner than the regular thickness.In some more preferred embodiments, the compressed filtration regioncovers between 8 and 20% of the filter media sheet, and the compressedthickness is between 30 and 50% thinner than the regular thickness.

In some embodiments, the compressed thickness may be between 0.5 and 1.3millimeter and wherein the regular thickness is between 1.5 and 3millimeter.

According to an aspect and feature, a filter media element can have atleast a MERV 13 efficiency rating, and a volumetric dust holdingcapacity of greater than 0.040 grams/cubic-inch at measured according toASHRAE 52.2-2012 standard, and more preferably a volumetric dust holdingcapacity greater than 0.055 grams/cubic-inch.

It is a feature that the adhesive elements may be laid upon the filtermedia sheet along a continuous or discontinuous bead that forms a linearpath extending transverse relative to the pleat tips, the continuous ordiscontinuous bead being laid on both the inlet face and the outlet faceof the filter media sheet.

Another feature comprises a plurality of embossments formed into thefilter media sheet and intersecting the compressed filtration regionsand the remainder filtration regions, the embossments being formed inrows that run transverse to the pleat tips, wherein the embossments areproximate pleat tips, and wherein the embossments are on formed intoadjacent members of the pleat flanks and project toward each other tonarrow a pleat valley defined between adjacent members of the pleatflanks at a location proximate pleat tips, and wherein the adhesiveelements extends over the embossments and extend along the rows.

In some embodiments, the different filtration regions form a pattern onthe outlet face the compressed filtration region extending diagonallyrelative to the pleat tips.

It is another feature, that the compressed filtration region may beformed into the outlet face wherein the outlet face comprises elevationsand depressions corresponding to the remainder filtration region and thecompressed filtration region, respectively.

It is another feature that the filter media sheet may be a composite ofcoarser fibers and finer fibers, the coarser fibers having a diametergreater than 2 micron and the finer fibers having a diameter of lessthan 2 micron, wherein a heavier relative coverage of coarser fibers arearranged proximate the inlet face compared to an outlet face of thefilter media sheet, the spaced region being spaced from the inlet faceby at least 0.2 millimeter, and wherein a heavier relative coverage offiner fibers are arranged in the spaced region of the filter media sheetas compared to the inlet face.

Another feature may be that the coverage of fine fiber may be closer tothe outlet face as compared to the inlet face.

Another feature may be that the filter media sheet is a single layercomposite and not multilayer laminated.

Another aspect is directed toward a panel filter comprising the filtermedia element described according to any of the aspects or featuresabove or below. The panel filter includes a border frame with the filtermedia element being surrounded by the border frame, and wherein thefilter media element defines an envelope size with a first and secondmutually perpendicular spans of between 12 and 36 inches; and a depth ofbetween 1 and 12 inches.

A feature may be that between 1.5 and 4.5 pleats per inch are provided.

Another aspect is directed toward a method of using a panel filterelement described according to any of the aspects or features above orbelow. The method comprises flowing air through the air filtrationsystem, the air filtration system comprising a housing having a flowpath conveying air to at least one of an HVAC system, air inlet for gasTurbine engine, and an industrial process application, and the panelfilter being installed in the housing with the inlet face disposedupstream along the flow path relative to outlet face.

It is a feature that such method may be in an air filtration system thatis free of a back-pulse mechanism.

Another aspect is directed toward a method of using any of the filtermedia elements described herein comprising advancing air flow throughthe filter media element in a direction from the upstream extent to thedownstream extent to cause particulates to load in a depth of the filtermedia.

Other aspects described below may also be used in conjunction with theaspects or features above.

Another aspect is directed toward a filter media element comprising afilter media sheet having an inlet face and an outlet face, the filtermedia sheet being pleated to include a plurality of pleat tips includinga first set of pleat tips along an upstream extent and a second set ofpleat tips along a downstream extent with pleat flanks extending betweenthe first set of pleat tips and the second set of pleat tips; whereinthe filter media element has at least a MERV 14 efficiency rating(according to ASHRAE 52.2-2012 standard), and a volumetric dust holdingcapacity of greater than 0.040 grams/cubic-inch according to ASHRAE52.2-2012.

Another aspect is directed toward a filter media element comprising afilter media sheet having an inlet face and an outlet face, the filtermedia sheet being pleated to include a plurality of pleat tips includinga first set of pleat tips along an upstream extent and a second set ofpleat tips along a downstream extent with pleat flanks extending betweenthe first set of pleat tips and the second set of pleat tips. Differentfiltration regions including a compressed filtration region and aremainder filtration region are formed into the filter media sheetproviding the filter media with different filtering properties in thedifferent filtration regions. The compressed filtration region is formedinto the outlet face wherein the outlet face comprises elevations anddepressions corresponding to the remainder filtration region and thecompressed filtration region, respectively.

Another aspect is directed toward a method of making a filter,comprising: advancing a filter media sheet having an inlet face and anoutlet face and with different filtration regions including a compressedfiltration region and a remainder filtration region formed into thefilter media sheet providing the filter media with different filteringproperties in the different filtration regions through a heater; heatingthe filter media sheet; thereafter embossing the filter media sheet withembossments; scoring the filter media sheet with scores runningtransvers to the advancing; laying continuous or discontinuous adhesivebeads along the filter media sheet and over the embossments; and foldingthe filter media sheet along the scores to provide a plurality of pleattips including a first set of pleat tips along an upstream extent and asecond set of pleat tips along a downstream extent with pleat flanksextending between the first set of pleat tips and the second set ofpleat tips; and a plurality of adhesive elements extending betweenadjacent members of the pleat flanks and attaching adjacent members ofthe pleat flanks to separate and space the pleat tips in a spacedrelation.

It is a feature that during the embossing, the embossing maintains athickness of the filter media sheet to within 15% of an originalthickness.

Other aspects, objectives and advantages of the invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention and,together with the description, serve to explain the principles of theinvention. In the drawings:

FIG. 1 is a perspective view of a panel filter element according to afirst embodiment of the present invention;

FIG. 2 is a frontal view of a rectangular filter media pack that mayitself be used as a panel filter or, more preferably, that may be framedsuch as being employed in the panel filter of FIG. 1;

FIG. 3 is a partly schematic cross section of FIG. 1 taken through oneof the adhesive beads of adhesive spacers; shown without embossments,the compressed/remainder filtration regions nor flattened pleat tipsshown to avoid undue complication in this FIG. (See FIGS. 4A-4C and 5for further details as to these other features).

FIG. 4 is a schematic top view of the embossed and adhesively spacedfilter media viewed from either of the inlet and outlet sides, whichviews are the same, and taken through the pleat tips parallel to one ofthe inlet and outlet faces, without the compressed/remainder filtrationregions shown and with the glue not covering the pleat tips in thisillustration.

FIG. 4A is a cross section of the filter media pack that may be takenabout line 4A of FIG. 3;

FIGS. 4B and 4C are cross sections of filter media that may be takenabout lines 4B-4B and 4C-4C respectively of FIG. 4A.

FIG. 5 is a cross-section and perspective illustration of a filter mediasheet having compressed and remainder filtration regions and shown priorto embossment operations in the pleater, and schematically showing aheavier concentration of finer fibers in an spaced region of the mediawith artificial lines drawn into the cross section to delineate anspaced region

FIGS. 5A and 5B are enlarged portions of the cross section shown in FIG.5.

FIG. 6 is an exploded assembly view of the panel shown in FIG. 1;

FIG. 7 is a microscopic photograph of a cross sectional cut through thefilter media according to an embodiment of the present invention showingthe compressed and remainder filtration regions and the coarse fibers ofthe filter media;

FIG. 8 is a photograph of a filter media along the downstream sideaccording to an embodiment of the present invention showing thecompressed and remainder filtration regions in a pleated and embossedassembled form with adhesive spacers;

FIG. 9 is a schematic side elevation view of a pleater and method forforming the filter media according to the embodiments above.

FIG. 10 is a photograph of the downstream or outlet face of a dimpledsheet that has not yet been scored or pleated that is useable in anembodiment of the present invention.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-3 illustrate embodiments of a panel filter 10 of the presentinvention. The panel filter 10 generally includes a pleated filter media12 that is arranged in a rectangular card-like structure and that ismaintained in that rectangular card-like configuration by a suitablesupport structure such as a rectangular plastic frame 14, as shown.

The pleated filter media 12 is formed from a relatively thin porousmaterial such as an entanglement of polymeric fibers and/or cellulose orglass fibers that permits air to readily pass through, but interceptssolid particles such as dust, lint and the like. The panel filter 10illustrated is particularly suited for Heating, Ventilation and AirConditioning (HVAC) systems, and other industrial applications such asair inlet filters (main filter or pre-filters) for gas turbine engines,or other industrial applications such as animal confinement buildings,clean room filtration, manufacturing or energy process filtration. Thefilter media is folded into multiple pleats 16 to provide sets of pleattips 35 on each side (both inlet and outlet sides) of the panel filter10.

Pleats are provided with the full face of pleat flanks exposed duringuse (not blinded) with structural support discussed herein with a pleatdensity typically between 1.5 and 4.5 pleats per inch.

As for size, for typical applications, the panel filter 10 may span afirst lateral span 18 of between 12 and 30 inches and a second lateralspan 20 transverse to the first span that is also between about 12 and30 inches. Pleat depth can be measured normal to these spans 18 and 20.

In various embodiments, the pleat depth may be between 1 and 12 inches(fractions being rounded up in this instance considering that the panelfilter element need only fit an envelope that size; thus a ⅞th inchpleat depth would be considered a 1 inch depth filter). For manyembodiments with a plastic frame for many industrial applications, thepleat depth between 4 inches and 12 inches, with lateral width spanseach spanning between 12 inches and 30 inches.

In the embodiment shown in FIG. 1 and also demonstrated by FIGS. 3 and6, each of the inlet side 24 and outlet side 26 of the pleated filtermedia 12 are supported by the frame 14, which may comprise multiplechannel parts that are assembled together as shown in the embodiment ofFIG. 6. Alternatively, paperboard frames, border frames, edge bandframes or the like, may be used. The pleated filter media 12 is glued tothe channels of the frame 14 along a rectangular periphery that alsoprovides a rectangular border seal between the filter media and theframe.

With this configuration and with adhesive 28 laminated to the innersurface of the frames 14, it can be seen that the filter media 12 issupported and by the frame channels 30 that extend along an inside ofthe frame 14.

To achieve an organized filter media configuration and support for thefilter media 12, the embodiment employ adhesive spacer beads 36 whichmay be continuous or discontinuous, and which are laid down by anadhesive bead line applied upon both the inlet side 24 and outlet side26 of the pleated filter media during manufacture. The beads 36, serveto provide structural support to the pleated filter media to hold thestructure into a rectangular filter media pack 22.

Generally, the adhesive spacer beads 36 are continuous or discontinuousstrips of adhesive that are laid as the media is being run in thedirection of the second span in a continuous manner over each of theinlet side 24 and outlet side 26 to form the adhesive spacer beads 36 onopposing sides of the filter media, thereby forming the filter mediapack 22.

As can be seen in FIGS. 3, and 4A-4B, the adhesive spacer beads 36therefore extend up and over pleat tips and down partially into pleatvalleys along the pleat flanks and therefore at least partially into theV-shaped channels formed between adjacent pleat flanks. Alternatively,in some embodiments the adhesive beads 36 may reach all the way to thebottom of such V-shaped channels as the adhesive spacer beads are laidcontinuously.

The adhesive spacer beads may be laid down in parallel lines at aspacing (relative to the next adjacent adhesive bead) between ½ and 4inches and in some embodiments, more preferably between 1 and 2 inches.This provides sufficient structural support to maintain the pleat shapeand V-shaped channels 37 with sufficient open volume to provide airflowwithout undue restriction. The adhesive spacer beads 36 also affordsupport to prevent the pleats from collapsing and contacting each otherto prevent blinding off the filter media during operation.

For example, V-shaped channels 37 do not deform or collapse very muchduring use, which maintains airflow into the channels to move throughfilter media of pleat flanks. As a result, much more of the surface areaof the pleated filter media 12 is exposed for full filtration and dustloading purposes. Further, the configuration allows for dust cakeaccumulation without prematurely filling or blocking the V-shapedchannels 37 with this pleat density and support structure configuration.

To assist in the spacing and structural integrity, various embossments38 are preferably provided to widen the pleat flanks at the select areaswhere the adhesive spacer beads 36 are laid down. This can be seen, forexample, in FIG. 4 whereby embossments are formed such as by heatsetting and/or compression forming into the pleat flanks 34 every one to2 inches (or between ½ and four inches in some other embodimentsdepending upon the spacing of the adhesive spacer beads 36). Embossments38 provided a shorter span needed for the adhesive to bridge across theV-shaped channels 37 between adjacent pleats. Additionally, additionalembossments 39 may be interspaced between the adhesive spacer beadembossments 38 as illustrated also at a similar spacing of the adhesivespacer bead embossments 38. These other embossments 39 do not receive aglue bead, but provide for additional structural support and alsoprevent flat surface-to-surface contact between filter media along thepleat flanks 34 in response to airflow forces during use.

For clarity, embossments 38 and 39 should not be confused and are notthe same as the compressed and remainder filtration regions as describedherein. Instead, the thickness of the media at the embossments mayremain the same (i.e. compression or expansion as a result of embossrolls if any is insignificant, less than 15% of thickness) as comparedto the compressed and remainder filtration regions that have notablydifferent filter media thicknesses by design.

Further, point bonding where different discrete layers of media arewelded together at point bonds also is not to be confused withcompressed filtration regions and remainder filtration regions. Inparticular, point bonding at those locations typically eliminates thefiltration of that region rendering non-filtering. Further, inembodiments, typically a one integrated layer composite media is used orchosen, although multiple discrete layers composites that are laminatedtogether may also be used in alternative embodiments.

Referring to FIG. 2, it can be seen that this may provide a filter mediapack 22 that has employed the adhesive spacer beads 36 and embossments38, 39 (of FIG. 4) such that the filter media pack 22 is ready to beframed via frame 14 for use to create the panel filter shown in FIG. 1.

As evident in embodiments above, to provide a support structure forsupporting the media in a rectangular configuration, various frames,scrims, bands and the like may be used in addition to, or in thealternative to those disclosed according to the embodiments describedabove. Support structures in various other embodiments of the presentapplication may be used such as disclosed in U.S. Patent PublicationNumber 2012/0167535 entitled, “Self Supported Pleated Panel Filter WithFrayed Edges”; U.S. Patent Publication Number 2010/0269468 entitled,“Panel Filter”; U.S. 2010/0269467 entitled, “Panel Filter”; U.S. Pat.No. 7,537,632 entitled, “Panel Filter With Frame”; U.S. PatentPublication Number 2005/224170 entitled, “Method and System for MakingFilters”; and U.S. Pat. No. 5,782,944. Each of these patents areincorporated by reference in their entireties for support structures andpanel filter details may be used as alternatives or an addition to thosein embodiments discussed specifically herein.

Some embodiments may alternatively or additionally include pleatsupports and spacers between adjacent pleat flanks 34 (FIG. 3). Forfilter elements configured to operate in high-flow-rate environments,spacers, such as plastic finger spacers or bars, or hot-melt adhesivesspaced at regular intervals, may be placed at regular intervals alongthe pleated filter media to add structural rigidity and preventdeformation of the media.

In addition to being pleated with heat setting of the pleats, the filtermedia may also be embossed to add structural rigidity, to furtherincrease surface area, and to increase amount of media that can bemanipulated into a volume for the panel filter 10. A method of embossedfilter media is described in U.S. Pat. No. 6,685,833. U.S. Pat. No.5,290,447, U.S. Pat. No. 5,804,014 and DE 19755466 A1 also describemethods of embossing that, in some embodiments, may be applied to thecomposite filter media of the present invention as an addition oralternative. Each of these patents are incorporated by reference intheir entireties, as these or other pleating and embossing technologiesmay be used.

For example, integrally formed embossments 38 (grooves, folds orwrinkles extending between pleat tips 35 and between inlet and outletfaces) formed into the filter media and adhesive spacer beads 36 areillustrated on the filter media of filter media pack 22 as shown inFIGS. 1-5. Various numbers and arrangements of embossments can beprovided. The adhesive beads are on adjacent pleat tips and extend alongpleat sides and attach to each other as shown. This provides consistentpleat spacing and structural integrity to the pleated filter pack.Adjacent pleat tips may be spaced between ½ and 2 centimeters to compacta substantial amount of filter media into the envelope while at the sametime keeping an open flow structure to accommodate high air flowcapacity.

Also, the pleat tips may be flattened with two creased edges 40 and aflat 42 therebetween as schematically illustrated in FIG. 4 and bettershown in FIG. 4B. Flats 42 may between 0.5-2.5 millimeters wide in someembodiments.

To better facilitate for structural integrity and high air flow, somepreferred embodiments may include additional pleat supports and spacersbetween adjacent pleat flanks 34. For filter elements configured tooperate in high-flow-rate environments, spacers, such as plastic fingerspacers or hot-melt adhesives spaced at regular intervals, may be placedat regular intervals along the pleated filter media to add structuralrigidity and prevent deformation of the media. In addition to beingpleated with heat setting of the pleats (e.g. with bi-component filtermedia with high melt and low melt fibers and/or high melt and low meltcomponents in fibers), the filter media may also be embossed to addstructural rigidity, to further increase surface area, and to increaseamount of media that can be manipulated into a volume for panel filter.Any of these aforementioned structures may be employed as supportstructure to maintain a rectangular configuration as an alternative toor in addition to frames (e.g. die cut frames and/or edge banding).

In accordance with various aspects, the embossed pleated filter media 12may be made with a non-uniform filter media sheet 50 having an inletface 52 and an outlet face 54 (the inlet face 52 and the outlet face 54facing the inlet side 24 and the outlet side 26, respectively). Theinlet face 52 and the outlet face 54 may be arranged in a predeterminedorientation relative to air flow 56 as explained herein.

The filter media sheet 50 includes different filtration regionsincluding a compressed filtration region 58 and a remainder filtrationregion 60 formed into the filter media sheet. This provides the filtermedia with different filtering properties in the different filtrationregions.

The compressed filtration region 58 and a remainder filtration region 60may be formed in accordance with US Patent Publication No. 2013/0269529to Jung et al. and assigned to Irema Filter GmbH, the entire disclosureof which is hereby incorporated by reference. The filter media may bearranged according to Jung et al.

However, contrary to the '529 publication to Jung et al., in a preferredembodiment, the compressed filtration region 58 is formed into theoutlet face 54 such that the outlet face 54 comprises elevations anddepressions corresponding to the remainder filtration region 60 and thecompressed filtration region 58, respectively. This creates a differentmechanism for filtrations of particulates.

Further, in many applications, these filters may not be employed with areverse pulse release mechanism, but instead act as depth loading panelfilters. This may be used to provide a high efficiency (e.g. MERV 13 or14 or higher) in combination with a high dust loading capacity.

The different filtration regions may form a pattern 62 on the outletface 54, with the compressed filtration region comprising compressedgrooves or indentations 64 extending diagonally relative to the pleatsor pleat tips. With the orientation, this may create bag like pocketswith the remainder filtration region 60 on the outlet face 54.

Preferably, the compressed filtration region 58 covers between 5 and 50%of the filter media sheet, more preferably between 8 and 20% (with theremainder filtration region 60 comprises the remainder percentage).

In some embodiments, the compressed filtration region 58 defines acompressed thickness, and the remainder filtration region comprises aregular thickness, the compressed thickness being between 20 and 70%thinner than the regular thickness, more preferably between 30 and 50%.The compressed thickness being measured at the bottoms of the groovesthat form the dimples that provide the thinnest locations.

In some embodiments, the compressed thickness is between 0.5 and 1.3millimeter, and wherein the regular thickness defined by the remainderfiltration region 60 is between 1 and 4 millimeter (more preferablybetween 1.5 and 3 millimeter).

Panel Filter Sizes & Media Pack Amounts & Pleat Spacing

Generally in the panel filter art, the sizes are relatively standard. Acommon size is a 24 inch×24 inch×4 inch filter. This means the filterwill fit an envelope of that size but is typically a bit smaller toallow for easy installation. For example, the actual depth of the filterframe may be 3 and ¾ inch and the pleat depth about 3 and ¼ inch for a 4inch fitting filter. Therefore, useful measures are made using thesedepths.

Filter Medias

One preferred filter media includes grade designations TFN80G and TFN83Gcommercially available from Irema Filter GmbH of Pastbauer-Pavelsbach,Germany (herein “Irema”), which have a loft or caliper thickness ofabout 2 millimeters. This filter media sheet comes with the formedcompressed filter region and the remainder region and can be then runthrough a pleating and embossing machine to create the panel filterelements. These types of media such as available from Irema with thecompressed filtration regions 58 and the remainder region 60 may bereferred to as “dimpled media” herein.

Other suitable filter medias are available from other suppliers. Forexample, media grades of Transweb, LLC of Vineland, N.J. include variouspermanent electret filter medias, that can also be dimpled into apattern and used in the various embodiments.

Various electret filter medias may have an electrostatic charge such asby way of fluorine atoms. Fluorinated polymers, chemical additives orplasma fluorination for example may be used to impart fluorine atoms.

In an embodiment, the filter media is preferably not a surface loadingmedia, but may be a depth loading filter media. The filtrationefficiency may be obtained from fine fibers less than 2 micron andpreferably less than 1 micron contained within the depth of the filtermedia and/or applied to the outlet face. In an embodiment, the filtermedia sheet maybe a composite of coarser fibers and finer fibers, thecoarser fibers having an average diameter between 2 and 10 micron andthe finer fibers having an average diameter of less than 1 micron (alsoknown as nanofibers). A variety of different sized coarse fibers may beemployed as shown in FIG. 7, which is a cross-section through the Iremafilter media noted above.

Further, and as shown in FIG. 7, and consistent with a depth filtermedia, a heavier relative coverage of the coarser fibers are appliedwith the coarsest fibers arranged proximate the inlet face 52 comparedto an outlet face 54 of the filter media sheet. Further, a spaced region66 may be spaced from the inlet face 52 by at least 0.2 millimeter(preferably at least 0.5 millimeter) such as shown schematically shownin FIG. 5 (see also FIG. 7) with a heavier relative coverage of finerfibers under 2 micron (and more preferably under 1 micron) that arearranged in the spaced region 66 of the filter media sheet 50 ascompared to the inlet face 52 or inlet region (the inlet region 70 beingthe region upstream of the spaced region 66; and the spaced region 66including the outlet region 68).

Considering that the media may be considered depth loading, the coverageof fine fibers within the spaced region are preferably closer to theoutlet face 54 as compared to the inlet face 52. This can be seen in anembodiment example with finer fibers shown proximate the dimpled outletface in the microscopic image of FIG. 7 (finer nanofibers not seen inFIG. 7 may also be present and disposed proximate the outlet face and/orin the spaced region 66).

In embodiments, the filter media may comprise non-woven polymeric suchas polyolefin fibers with a basis weight of between 100 and 200 gramsper square meter and a media thickness (measured at remainder filtrationregions) of between 1 and 4 millimeter, thereby providing for high loft.The high loft provides a high dust loading capability and airpermeability.

To provide for heat setting and embossing of pleats, the filter mediabase preferably includes a component polymeric structure including ahigh melt polymer and a low melt polymer.

The selected media may have an air permeability of between 45 and 600cfm at 0.5 inch WG pressure according flat sheet media testing. The airpermeability may depend upon application, as prefilters with MERV 8applications for gas turbine may have higher flow rate media, whileengine air applications may have lower flow rate media.

According to certain embodiments, the filter media sheet is a compositeof coarser fibers and finer fibers, the coarser fibers having a diameterbetween 2 and 10 micron and the finer fibers having a diameter of lessthan 2 micron, and preferably less than 1 micron.

According to certain embodiments, a heavier relative coverage of coarserfibers is arranged proximate the inlet face compared to a spaced regionof the filter media sheet. The spaced region may be defined as beingspaced from the inlet face and the outlet face by at least 0.2millimeter.

Further the media sheet 50 may have a heavier relative coverage of finerfibers are arranged in the spaced region of the filter media sheet ascompared to the inlet face.

Also in a different embodiment, the coverage of fine fiber may be closerto the inlet face as compare to the outlet face.

Further, for higher efficiency and primary filter applications, thefilter media element has at least a MERV 13 efficiency rating (accordingto ASHRAE 52.2-2012 standard), and more preferably at least a MERV 14rating.

With the media and structural arrangement illustrated in the figures andthe examples of FIGS. 6 and 7, a much higher dust holding capacity thanheretofore can be obtained in a MERV 13 or better filter. Specifically,unlike the typical prior art, a volumetric dust holding capacity ofgreater than 0.040 grams/cubic-inch can be achieved for a standard 2foot×2 foot filter, the volumetric dust holding capacity measuredaccording to ASHRAE 52.2, and in fact the volumetric dust holdingcapacity can be achieved that is greater than 0.050 grams/cubic-inch, oreven greater than 0.060 grams/cubic-inch.

In alternative embodiments and to achieve additional dust holdingcapacity, the polymeric fibers may contain fluorine or other agent toprovide an electrostatic charge to provide the filter media. Forexample, the filter media may be charged to an electret with surfacefluorination, which may be according to U.S. Pat. No. 6,419,871,assigned to Transweb, LLC. Other fluorination methods may include theaddition of fluorochemicals according to U.S. Pat. Nos. 5,411,576 and5,472,481 to Jones et al and/or U.S. Pat. No. 5,908,598 to Rousseau etal. Each of the patents is hereby incorporated by reference.

Manufacturing Methodology and Formation

Surprisingly, it has been found that dimpled media can be processed withembossing type pleater machines without destroying the dimples duringthe embossing process if process conditions are controlled.

Further, surprisingly it has also been found that arranging the dimples(compressed regions) along the downstream or outlet face of the mediawhile leaving the upstream or inlet face flat (but for the embossments),also generates substantial additional dust holding capacity.

A method of processing according to certain embodiments can be done oncommercially available pleating and embossing machines as commerciallyavailable from TAG, GMBH of Teltow, Germany, and as modified byFiltration Advice, LLC of Miami, Fla. (formerly known as LPDTechnologies, Inc.), with the pleater assembly 110 shown in FIG. 9.

The pleater assembly 110 has a tensioning assembly (not shown) tocontrol sheet tension not shown that receives a continuous filter mediasheet 50 from a dimpled media roll 112. The sheet on the roll 112already has formed therein the dimples of the compressed filtrationregion 58 and the remainder region 60 that may take a dimpled likepattern 62 with “dimples” as previously noted.

After coming off of the roll 112, the dimpled media sheet 50 passesthrough an oven to soften the media for embossing operations. Pre-heatsettings play a role in process efficiency and filter performance anddepends upon run line speed, so the oven temperature may not be asimportant as the media temperature. The heat softens the media, makingit more malleable so that embosses can be imparted into the media suchthat the shape is retained. The heat and malleability of the media areset so that the media stretches rather than ruptures during thescore/embossing process.

Once passing through the oven 114, the filter media is pulled throughpleating and embossing rolls including top roll 116 and bottom roll 118that are spaced apart relative to the thickness of the media. Theserolls 116, 118 form the embossments for the adhesive spacer attachmentsand the scores for forming the pleat tips and pleats.

The adjustable parameters associated with the set-up of the pleaterrollers 116, 118 can greatly effect process efficiency and filterperformance As shown the pleater tooling is a set of driven precisionsteel rollers 116, 118 that are mounted perpendicular to web of filtermedia sheet 50. The rollers have embossment features incorporated intothe rollers. Lengthwise slots are also machined into the rollers atprescribed arc lengths apart where score bars are mounted. The rollersalso contain female mating surface that allow the meshing of the maleembosses and score bars.

While conventional running of the pleating assembly 110 may be employed,the rollers 116, 118 can be adjusted in the following manner byadjusting the roller gap and adjusting the pleat score bars as necessaryto generate deeper scoring independent of embossments and/or makingshallower embossments in some circumstances. Other than theseadjustments, conventional running of the pleater assembly 110 may beemployed in terms of line speed and tensioning.

As to the roll gap, the distance between the two rollers 116, 118 can beadjusted. This adjustment determines the emboss and score depth impartedon the media. Varying the roller gap and emboss depth can reduce theemboss height imparted on the media. As the embosses become shallower:the required filter pleat count increases, the embosses become lessdefined and weaker (collapse under pressure easier) and embosses becomeless likely to be damaged by ruptured media. As embosses are adjusted topenetrate deeper: the embosses become taller which reduces the finishedpleat count, the embosses become stronger as the shape is well formedinto the media and the risk of media damage is increased. Contrary toother media types, in an embodiment, the media introduces an additionalvariable into the process development as the filter performance can bereduced if the “dimples” are crushed and do not rebound during theembossing process.

The score depth is increased or decreased as the roller gap is adjusted.The score depth must be sufficient enough to initiate a fold during thepleat gathering process. The score depth can be adjusted independentlyof the roller gap settings. As to the efforts of preserving the“dimples” associated with the filter media sheet 50, the pleater rollergap between rolls 116, 118 may be adjusted.

Once passing through the rolls 116, 118, the media sheet 50 now scoredand embossed passes through an adhesive applicator 120, 122 (top andbottom applicators) that applies suitable adhesive beads 36 (see alsoFIG. 2) typically at least over the score pleat tips on both upstreamand downstream sides of the filter media sheet, in a continuous ordiscontinuous manner in rows that run transverse and preferablyperpendicular to the pleat tips.

Pull rolls 124 eventually feed the sheet 50 to a folding section 126that collects the pleats and forms the pleated filter media 12 with theadhesive beads shown schematically over the pleat tips in FIG. 9 (seeother FIGS. 1-8 for actual configuration). The pleated filter media 12is then conveyed on a belt conveyor and transported to a cutting station130, where the continuous sheet is cut into the correct size andrectangular shape to become the rectangular filter media packs 22.

With embodiments of the present invention, dust holding capacity can beincreased. For example, the existing Legacy Filter sold by the presentassignee that uses the embossments and adhesive spacers and run on theLPD modified pleater noted above has the following performance for twopopular sizes:

24″×24″×4″—No header

Initial Resistance to Air Flow at 1968 CFM=0.46″ WC MERV 14 Efficiency

Dust Holding Capacity=74 grams49.1 sq. ft. of media.Actual filter volume 2049 in³

Dust/in³=0.03611

24″×24″×12″—No header

Initial Resistance to Air Flow at 1968 CFM=0.38″ WC MERV 15 Efficiency

Dust Holding Capacity=234 grams97.3 sq. ft. of media.Actual filter volume 6487 in³

Dust/in³=0.03607

When the Irema grade TFN83G dimpled media was processed through thepleater with the dimples or compressed regions on the downstream/outletface of the media sheet, the following results were obtained:

24″×24″×4″—No header

Initial Resistance to Air Flow at 1968 CFM=0.44″ WC MERV 14 Efficiency

Dust Holding Capacity=134 grams53.1875 sq. ft. of media.Actual filter volume 2049 in³

Dust/in³=0.06539

24″×24″×12″—No header

Initial Resistance to Air Flow at 1968 CFM=0.27″ WC MERV 15 Efficiency

Dust Holding Capacity=517.5 grams123.78 sq. ft. of media.Actual filter volume 6487 in³

Dust/in³=0.07977

As can be seen from test results, nearly double the filter's dirtholding capacity can be achieved which adds value to the product byeither extending the change interval or providing a lower air flowrestriction over the same range as the current product thereby loweringthe energy consumption of the filtration system.

It will also be appreciated that certain applications may not require asmuch improvement and therefore less efficient or less dust holdingcapacity can be achieved. However, improvements in dust holding capacitywere observed by the provisions of (a) placing the dimpled pattern(compressed region) on the downstream side and outlet face of the media,(b) using the dimpled media in combination with adhesive spacers andembossments, (c) selection of a media that is depth loading rather thansurface loading, and (d) operating the pleater/embossing assembly in amanner so as to maintain integrity of the dimples. Any of these areuseful by themselves in embodiments, but in combination in otherembodiments are advantageous.

Testing Standards

For the tests and standards discussed herein, ANSI/ASHRAE Standard52.2-2012 applies. As such, the following can be used: ASHRAE #1 testdust obtained from Powder Technology Inc. This test dust consists of 72%ISO 12103-1 A2 Fine, 5.0% milled cotton linters and 23% powdered carbon.This dust is specified for use in ANSI/ASHRAE Standard 52.2-2012. Testconditions include air temperatures between 10° C. and 38° C. (50° F.and 100° F.), relative humidity between 20% and 65%. Test Aerosol shallbe polydisperse solid-phase dry potassium chloride (KCl) particlesgenerated from an aqueous solution. Particles shall be counted with anoptical particle counter with wide angle as described in ANSI/ASHRAEStandard 52.2-2012 test standard. Face velocity for testing is 492ft/min with a cumulative dust holding capacity measured at 1.50 WGfilter restriction.

All references, including publications, patent applications, and patentscited herein are hereby incorporated by reference to the same extent asif each reference were individually and specifically indicated to beincorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

What is claimed is:
 1. A filter media element, comprising: a filtermedia sheet having an inlet face and an outlet face, the filter mediasheet being pleated to include a plurality of pleat tips including afirst set of pleat tips along an upstream extent and a second set ofpleat tips along a downstream extent with pleat flanks extending betweenthe first set of pleat tips and the second set of pleat tips; aplurality of adhesive elements extending between adjacent members of thepleat flanks and attaching adjacent members of the pleat flanks toseparate and space the pleat tips in a spaced relation; and differentfiltration regions including a compressed filtration region and aremainder filtration region formed into the filter media sheet providingthe filter media with different filtering properties in the differentfiltration regions.
 2. The filter media element of claim 1, wherein thecompressed filtration region covers between 5 and 50% of the filtermedia sheet, with the remainder filtration region comprising theremainder and, wherein the compressed filtration region defines acompressed thickness, and the remainder filtration region comprises aregular thickness, the compressed thickness being between 20 and 70%thinner than the regular thickness.
 3. The filter media element of claim2, wherein the compressed filtration region covers between 8 and 20% ofthe filter media sheet, and the compressed thickness is between 30 and50% thinner than the regular thickness.
 4. The filter media element ofclaim 2, wherein the compressed thickness is between 0.5 and 1.3millimeter and wherein the regular thickness is between 1.5 and 3millimeter.
 5. The filter media element of claim 1, wherein the filtermedia element has at least a MERV 13 efficiency rating, and a volumetricdust holding capacity of greater than 0.040 grams/cubic-inch at measuredaccording to ASHRAE 52.2-2012 standard.
 6. The filter media element ofclaim 5 wherein the volumetric dust holding capacity is greater than0.055 grams/cubic-inch.
 7. The filter media element of claim 1, whereinthe adhesive elements are laid upon the filter media sheet along acontinuous or discontinuous bead that forms a linear path extendingtransverse relative to the pleat tips, the continuous or discontinuousbead being laid on both the inlet face and the outlet face of the filtermedia sheet.
 8. The filter media element of claim 1, further comprisinga plurality of embossments formed into the filter media sheet andintersecting the compressed filtration regions and the remainderfiltration regions, the embossments being formed in rows that runtransverse to the pleat tips, wherein the embossments are proximatepleat tips, and wherein the embossments are on formed into adjacentmembers of the pleat flanks and project toward each other to narrow apleat valley defined between adjacent members of the pleat flanks at alocation proximate pleat tips, and wherein the adhesive elements extendsover the embossments and extend along the rows.
 9. The filter mediaelement of claim 1, wherein the different filtration regions form apattern on the outlet face the compressed filtration region extendingdiagonally relative to the pleat tips.
 10. The filter media element ofclaim 1, wherein the compressed filtration region is formed into theoutlet face wherein the outlet face comprises elevations and depressionscorresponding to the remainder filtration region and the compressedfiltration region, respectively.
 11. The filter media element of claim1, wherein the filter media sheet is a composite of coarser fibers andfiner fibers, the coarser fibers having a diameter greater than 2 micronand the finer fibers having a diameter of less than 2 micron, wherein aheavier relative coverage of coarser fibers are arranged proximate theinlet face compared to an outlet face of the filter media sheet, thespaced region being spaced from the inlet face by at least 0.2millimeter, and wherein a heavier relative coverage of finer fibers arearranged in the spaced region of the filter media sheet as compared tothe inlet face.
 12. The filter media element of claim 12, wherein thecoverage of fine fiber are closer to the outlet face as compared to theinlet face.
 13. The filter media element of claim 1, wherein the filtermedia sheet is a single layer composite and not multilayer laminated.14. A panel filter comprising the filter media element of claim 1, thepanel filter including a border frame, the filter media element beingsurrounded by the border frame, and wherein the filter media elementdefines an envelope size with a first and second mutually perpendicularspans of between 12 and 36 inches; and a depth of between 1 and 12inches.
 15. The panel filter of claim 14 wherein between 1.5 and 4.5pleats per inch are provided.
 16. A method of using the panel filter inan air filtration system including the panel filter of claim 14, themethod comprising flowing air through the air filtration system, the airfiltration system comprising a housing having a flow path conveying airto at least one of an HVAC system, air inlet for gas Turbine engine, andan industrial process application, and the panel filter being installedin the housing with the inlet face disposed upstream along the flow pathrelative to outlet face.
 17. The method of claim 16, wherein thecompressed filtration region is formed into the outlet face wherein theoutlet face comprises elevations and depressions corresponding to theremainder filtration region and the compressed filtration region,respectively.
 18. The method of claim 16, wherein the air filtrationsystem is free of a back-pulse mechanism.
 19. A filter media element,comprising: a filter media sheet having an inlet face and an outletface, the filter media sheet being pleated to include a plurality ofpleat tips including a first set of pleat tips along an upstream extentand a second set of pleat tips along a downstream extent with pleatflanks extending between the first set of pleat tips and the second setof pleat tips; wherein the filter media element has at least a MERV 14efficiency rating (according to ASHRAE 52.2-2012 standard), and avolumetric dust holding capacity of greater than 0.040 grams/cubic-inchaccording to ASHRAE 52.2-2012.
 20. The filter media element of claim 19,wherein different filtration regions are formed into the filter mediaincluding a compressed filtration region and a remainder filtrationregion formed into the filter media sheet providing the filter mediawith different filtering properties in the different filtration regions.21. The filter media element of claim 20, wherein the compressedfiltration region covers between 5 and 50% of the filter media sheet,with the remainder filtration region comprising the remainder and,wherein the compressed filtration region defines a compressed thickness,and the remainder filtration region comprises a regular thickness, thecompressed thickness being between 20 and 70% thinner than the regularthickness.
 22. The filter media element of claim 20, wherein thecompressed filtration region covers between 8 and 20% of the filtermedia sheet, and the compressed thickness is between 30 and 50% thinnerthan the regular thickness.
 23. The filter media element of claim 22,wherein the compressed thickness is between 0.5 and 1.3 millimeter andwherein the regular thickness is between 1.5 and 3 millimeter.
 24. Thefilter media element of claim 20, wherein adhesive elements are laidupon the filter media sheet along a continuous or discontinuous beadthat extends transverse relative to the pleat tips, and furthercomprising a plurality of embossments formed into the filter media sheetand intersecting the compressed filtration regions and the remainderfiltration regions, the embossments being formed in rows that runtransverse to the pleat tips, wherein the embossments are proximatepleat tips, and wherein the embossments are on formed into adjacentmembers of the pleat flanks and project toward each other to narrow apleat valley defined between adjacent members of the pleat flanks at alocation proximate pleat tips, and wherein the adhesive elements extendsover the embossments and extend along the rows.
 25. The filter mediaelement of claim 24, wherein the compressed filtration region is formedinto the outlet face wherein the outlet face comprises elevations anddepressions corresponding to the remainder filtration region and thecompressed filtration region, respectively.
 26. The filter media elementof claim 19 wherein the volumetric dust holding capacity is greater than0.055 grams/cubic-inch.
 27. The filter media element of claim 19,wherein the filter media sheet is a composite of coarser fibers andfiner fibers, the coarser fibers having a diameter greater than 2 micronand the finer fibers having a diameter of less than 2 micron, wherein aheavier relative coverage of coarser fibers are arranged proximate theinlet face compared to an outlet face of the filter media sheet, thespaced region being spaced from the inlet face by at least 0.2millimeter, and wherein a heavier relative coverage of finer fibers arearranged in the spaced region of the filter media sheet as compared tothe inlet face.
 28. The filter media element of claim 27, wherein thecoverage of fine fiber are closer to the outlet face as compared to theinlet face.
 29. A method of using the filter media element of claim 19,comprising advancing air flow through the filter media element in adirection from the upstream extent to the downstream extent to causeparticulates to load in a depth of the filter media.
 30. A filter mediaelement, comprising: a filter media sheet having an inlet face and anoutlet face, the filter media sheet being pleated to include a pluralityof pleat tips including a first set of pleat tips along an upstreamextent and a second set of pleat tips along a downstream extent withpleat flanks extending between the first set of pleat tips and thesecond set of pleat tips; different filtration regions including acompressed filtration region and a remainder filtration region formedinto the filter media sheet providing the filter media with differentfiltering properties in the different filtration regions; and whereinthe compressed filtration region is formed into the outlet face whereinthe outlet face comprises elevations and depressions corresponding tothe remainder filtration region and the compressed filtration region,respectively.
 31. The filter media element of claim 30, wherein thefilter media sheet is a composite of coarser fibers and finer fibers,the coarser fibers having a diameter greater than 2 micron and the finerfibers having a diameter of less than 2 micron, wherein a heavierrelative coverage of coarser fibers are arranged proximate the inletface compared to an outlet face of the filter media sheet, the spacedregion being spaced from the inlet face by at least 0.2 millimeter, andwherein a heavier relative coverage of finer fibers are arranged in thespaced region of the filter media sheet as compared to the inlet face.32. The filter media element of claim 31, wherein the coverage of finefiber are closer to the outlet face as compared to the inlet face. 33.The filter media element of claim 30, wherein the compressed filtrationregion covers between 5 and 50% of the filter media sheet, with theremainder filtration region comprising the remainder and, wherein thecompressed filtration region defines a compressed thickness, and theremainder filtration region comprises a regular thickness, thecompressed thickness being between 20 and 70% thinner than the regularthickness.
 34. The filter media element of claim 33, wherein thecompressed filtration region covers between 8 and 20% of the filtermedia sheet, and the compressed thickness is between 30 and 50% thinnerthan the regular thickness.
 35. The filter media element of claim 30,wherein the compressed thickness is between 0.5 and 1.3 millimeter andwherein the regular thickness is between 1.5 and 3 millimeter.
 36. Amethod of using the filter media element of claim 30, comprisingadvancing air flow through the filter media element in a direction fromthe upstream extent to the downstream extent to cause particulates toload in a depth of the filter media.
 37. A method of making a filter,comprising: advancing a filter media sheet having an inlet face and anoutlet face and with different filtration regions including a compressedfiltration region and a remainder filtration region formed into thefilter media sheet providing the filter media with different filteringproperties in the different filtration regions through a heater; heatingthe filter media sheet; thereafter embossing the filter media sheet withembossments; scoring the filter media sheet with scores runningtransvers to the advancing; laying continuous or discontinuous adhesivebeads along the filter media sheet and over the embossments; and foldingthe filter media sheet along the scores to provide a plurality of pleattips including a first set of pleat tips along an upstream extent and asecond set of pleat tips along a downstream extent with pleat flanksextending between the first set of pleat tips and the second set ofpleat tips; and a plurality of adhesive elements extending betweenadjacent members of the pleat flanks and attaching adjacent members ofthe pleat flanks to separate and space the pleat tips in a spacedrelation.
 38. The method of claim 37, wherein the compressed filtrationregion covers between 5 and 50% of the filter media sheet, with theremainder filtration region comprising the remainder and, wherein thecompressed filtration region defines a compressed thickness, and theremainder filtration region comprises a regular thickness, thecompressed thickness being between 20 and 70% thinner than the regularthickness.
 39. The method of claim 38, wherein the compressed filtrationregion covers between 8 and 20% of the filter media sheet, and thecompressed thickness is between 30 and 50% thinner than the regularthickness.
 40. The method of claim 38, wherein during the embossing, theembossing maintaining a thickness of the filter media sheet to within15% of an original thickness.